The present invention is related to a transmission technique of tools, and more particularly to a stabilizing mechanism for output torque of a transmission member.
It is known that high-pressure gas serves as the power source of some kinds of tools. For example, U.S. Pat. No. 6,024,180 discloses a pneumatic wrench having an output shaft. One end of the output shaft is drivable by an impact mechanism (such as double-hammer type and pin-clutch type) of the pneumatic wrench, whereby the output shaft can rotate and operate. The other end of the output shaft extends out of the housing of the pneumatic wrench for outputting power. In addition, U.S. Pat. No. 7,281,458 discloses a transmission shaft applicable to unspecific power or non-power tools. The transmission shaft is designed with torque-limiting protective effect.
It is found by this applicant that both the above conventional techniques apparently lack stabilizing/controlling system for the output torque. For example, the output shaft of U.S. Pat. No. 6,024,180 can only truly transfer the force provided by the hammering mechanism to outer side. Accordingly, the output torque is unstable. This is unsuitable for those working fields necessitating stable torque. With respect to U.S. Pat. No. 7,281,458, the transmission shaft is designed with torque-limiting protective effect. However, only when the application force exceeds the nominal transmitted torque, the engagement structure of the transmission shaft will jump aside to interrupt the transmission of torque. This is not helpful in stabilizing the output torque. That is, the value of the output torque under the nominal transmitted torque value is still unstable. Therefore, U.S. Pat. Nos. 6,024,180 and 7,281,458 have the same shortcoming.